Adjustable eccentric



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ADJUSTABLE ECCENTRIC Filed July 23, 1958 4 Sheets-Sheet 4 United rates Patent @free Patented May 8, 1962 3,033,055 ADJUSTABLE ECCENTRIC Werner Hiihnel, Stuttgart-Weiiimdorf, Germany, assignor to Trumpf & Co., Stuttgart-Weilimdorf, Germany Filed July 23, 1958, Ser. No. 750,535 Claims priority, application Germany July 26, 1957 6 Claims. (Cl. 74-571) The present invention relates to stamping machines in general, and more particularly to improvements in means for adjusting the length of stroke and the position of the ram in such apparatus.

In certain stamping machines of prior construction, the ram which, as is known, carries the movable die member, is customarily made of two portions which are joined by means of threads to be adjustable in axial direction whereby to change the overall length of the ram if adjustments in the latters position with respect to the work piece are desired. The disadvantage of such construction is in that in actual use, the connecting threads are subjected to considerable stresses when the ram reciprocates to bring the movable die member into and out of contact with the work piece. Consequently, the threads are destroyed after relatively short periods of use and the entire ram must be replaced. This adds considerably to the maintenance costs of such apparatus.

In a different type of stamping machines, changes in the rams position with respect to the work piece are made by adjustably mounting the table or work support, i.e. the latter is movable toward and away from the ram and the die member connected therewith. Such con struction, too, has a number of serious drawbacks the most important of which is in that the adjusting means are not easily accessible when the stamping is done by utilization of relatively large sheets of metallic or other material.

Attempts were already made to provide for adjustments in the rams position with respect to the work piece by the utilization of cams or eccentrics which cause the driving shaft, together with the ram and the driving connection therebetween, to be reciprocable in vertical direction. This arrangement necessitates the mounting of driving shaft in overhung position which is undesirable because of considerable stresses to which the shaft is subjected by the reciprocating ram during each stamping operation.

An important object of the present invention is to provide a stamping machine in which the ram and the movable die member are mounted in a manner to fully overcome the above enumerated drawbacks of known machine tools for similar purposes in that the machine operates with a stationary work support, in that the ram is made of a single piece of suitable material, and in that the driving shaft is rigidly supported in the head of the stamping machine.

Another object of the invention is to provide a machine of the above described characteristics in which the adjusting apparatus and the actuating means therefor occupy very little space.

A further object of the instant invention is to provide a stamping machine in which the driving shaft is so mounted that the stresses to which it is subjected are uniformly distributed. Therefore, the dimensions of driving shaft may be considerably below those of shafts in similar apparatus of known construction.

A still further object of my invention is to provide in a stamping machine means for adjusting the rams stroke and its position with respect to the work piece, which are so installed as to be actuatable from the same side of the apparatus.

The above and many other objects of the invention are attained by the provision of a stamping machine in which the driving shaft is formed with an eccentric portion between a pair of coaxial portions which latter are supported in the head of the machine, and in which the connecting member or strap for the ram surrounds a pair of eccentric members the inner of which controls the working stroke of the ram and the outer of which controls the rams position with respect to the work piece. The strap is swingably connected with the ram and, depending on the position of said two eccentric members, causes the ram to perform a longer or shorter stroke while at the same time controlling the latters position with respect to the work piece.

A further important feature of the improved construction is in that the eccentric portion of the driving shaft, the two eccentric adjusting members, the strap and the ram are positioned in the same plane and that, therefore, the axial length of eccentric members does not exceed the length of said eccentric portion. One coaxial portion of the driving shaft is connected with rotationimparting driving means, such as an electric motor, the other coaxial portion being concentrically received in a pair of sleeves each of which is coupled with one of the eccentric members to adjust the latters position when a change in the rams working stroke or in the rams position with respect to the work piece is desired. The sleeves are independently connected with suitable actuating means, such as a knob and a lever, the actuating means being preferably disposed at the same side of the head of my improved machine and being so mounted that the operator may independently adjust the rams stroke while its position with respect to the work piece remains unchanged, and vice versa.

The coaxial portions of driving shaft at both sides of its eccentric portion are received in suitable antifriction bearings at least one of which is installed in a pair of spaced walls forming part of the frame, and more particularly of the head of my machine tool so that any stresses transmitted by the ram to the strap and over the aforementioned eccentrics to the eccentric portions of driving shaft are uniformly distributed to allow the utilization of a driving shaft with dimensions much smaller than in similar stamping machines of known construction.

Additional improvements reside in the provision of spring-biased couplings between the adjusting sleeves and the actuating means therefor, and in the provision of indicating means to facilitate an operators work when a change in the rams working stroke or in its position with respect to the work piece is considered necessary.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of a specific embodiment when read in connection with the accompanying drawings, in which:

FIG. 1 is somewhat schematic elevational view of the entire machine tool showing that side of the device from which the improved adjusting means are manipulated;

FIG. 2 is an enlarged detail view of a part of FIG. 1 showing in greater detail the movable die member with operating means therefor and the stationary die member;

FIG. 3 is a front elevational view of the assembly shown in FIG. 2;

FIG. 4 is an enlarged vertical section taken on line IV--IV of FIG. 2, as seen in the direction of arrows;

FIG. 5 is a section illustrating a detail of FIG. 4 'With certain parts turned through about degrees from their position shown in FIG. 4;

FIG. 6 is an enlarged section taken on line VI-VI of FIG. 4, as seen in the direction of arrows, the position of parts therein shown corresponding to that when the ram and the movable die member perform their longest working stroke and when the movable die member is closest to the working piece;

FlG. 7 is a view similar to that of FIG. 6, showing the component parts in position they assume when the ram performs a shorter stroke and with the movable die member in the same position as in FIG. 6; and

FIG. 8 illustrates the parts shown in FIGS. 6 and 7 in a position in which the ram performs its shortest stroke and the movable die member cannot contact the work piece.

Referring now in greater detail to FIG. 1, the stamping machine therein shown comprises a substantially U- shaped frame or casing having an upper horizontal leg 11 and a lower horizontal leg 12. The latter constitutes a holder for the stationary member 15 of a die couple, the movable member 14 of said couple being removably connected to a connecting rod or ram 18 installed in a head 13 which is fixed to the free end of upper leg 11 by means of bolts 11:: or in any other suitable manner. The two side walls of the upper leg 11 are connected with each other by a top wall 11'.

As can be observed in FIG. 3, head 13 comprises a pair of spaced substantially parallel walls 13', 13", the former having connected thereto an electric motor 16 which imparts motion to movable die member 14. Motor 16 is coupled with the left-hand end portion 17' of a main or driving shaft 17, either directly or over a suitable gearing system (not shown). As before stated, member 14 is fixed to the lower end of the ram 18, the latter being restricted to vertically reciprocating movements by a guide member 19 forming part of the head 13 (see FIGS. 3 and 4). The upper end of ram 18 is connected to a strap 21 by means of a pivot pin 29. The latter is received in a bore 21a provided at the lower end of strap or connecting member 21. This member is formed with a second, relatively large bore 21b through which passes an eccentrically formed median portion 22 of driving shaft 17 and which, in addition, receives a pair of eccentrics 25, 39 whose purpose will be described in greater detail hereinafter. Connecting member or strap 21 causes vertically reciprocating movements of ram 18 and of die member 14 when the shaft 17 is rotated, the movement of member 21 being a composite movement consisting of oscillations about pivot pin and of upand-down movements in rhythm with the rotation of eccentric portion 22 and in dependency on the momentary position of adjusting eccentrics 25, 39.

Coaxial portions 17', 17" of driving shaft 17 are supported in respective walls 13', 13", of head 13 and rotate in respective antifriction bearings 23, 24. Eccentric portion 22 of shaft 17 is located between walls 13, 13". In this manner, all stresses and shocks to which the eccentric portion 22 is subjected are uniformly transmitted to bearings 23, 24 which, in turn, allows for considerable reduction in the dimensions of said bearings and of shaft 17 Eccentric portion 22 is received in the bore of an inner eccentric bushing 25 which latter determines the length of working stroke of ram 18 and of movable die member 14. Bushing 25 is rotatably about eccentric portion 22 and, as shown in FIG. 4, is formed with a radial groove or recess 26 which extends inwardly from its right-hand end face. Recess 26 receives a projection or key 27 which is provided at, and projects from, the left-hand end face of a hub-adjusting sleeve 28, the latter being formed with an axial bore to receive the portion 17" of driving shaft 17. Bearing 24 is coaxial with and surrounds the peripheral zone of an inner sleeve 28 which latter is formed with an enlarged portion of flange 29. The end face of flange 29 is provided with axially parallel bores 30 (see FIG. 5) for reception of slidably inserted pins 31 which connect sleeve 28 with, and are preferably nonremovably received in, aligned bores of a hub-adjusting handgrip member or knob 32. Member 32 has an axial bore 33 for reception of a reduced end portion 34 of driving shaft 17. A part of handgrip member 32 in its bore 33 is provided with axially parallel radially disposed teeth 37 which mesh with external teeth 38 on shaft portion 17" when the member 32 is in the position of FIG. 4. Handgrip member 32 is constantly urged in the direction toward and into abutment with fiange 29 of sleeve 28 by a coil spring 36 which latter abuts against the end faces of internal teeth 37 on the one hand, and against a retaining washer 35 on the other hand. Washer 35 is fixed to shaft portion 34 by means of a split ring 35a or the like. Thus, internal teeth 37 in spring-biased handgrip member 32 and external teeth 38 on shaft portion 17" constitutes two halves of a releasable clutch assembly which normally connects member 32 for rotation with driving shaft 17 and which may be rendered inoperative when the handgrip member 32 is moved to right against the expanding force of resilient element 36.

If the operator desires to change the working stroke of ram 18, clutch 37, 33 is released by moving the handgrip member 32 from its position of FIG. 4 into that shown in FIG. 5. It will be noted that the position of washer 35 and the length of pins 31 are so selected that the pins connect member 32 with flange 29 regardless of whether the clutch 37, 38 is in operative or inoperative position. Therefore, by rotating handgrip member 32 in the latters position shown in FIG. 5 either in clockwise or anticlockwise direction, pins 31 cause sleeve 23 to follow such angular movements about shaft 17 whereby the key 27 at the same time rotates the inner eccentric bushing 25 about eccentric portion 22 of the driving shaft. As soon as the proper setting of the rams stroke is found by the operator, he releases handgrip member 32 which is returned by resilient element 36 into the position of FIG. 4 in which the axially parallel teeth 37, 38 engage and thus connect member 32 for rotation with shaft '17.

As may be observed in FIGS. 4 and 6, the stroke of ram 18 is determined by the eccentricity e; of shaft portion 22 and the momentary eccentricity c of eccentric bushing 25. When the stamping machine is in use, bushing 25 rotates with shaft 17 and thus remains stationary with respect to eccentric shaft portion 22. In other words, the working stroke of ram 18 and of movable die member 14- which is connected therewith may be adjusted by changing the position of eccentric bushing 25 with respect to eccentric portion 22 of driving shaft 17 to change the throw of strap 21.

FIG. 6 illustrates members 22 and 25 in the position in which they cause ram 18, over connecting member or strap 21 and pivot 20, to perform its longest working stroke. It will be observed that eccentricity e of member 22 is added to the eccentricity e of bushing 25. In P16. 7, the relative positions of members 22 and 25 are such that the ram 18 performs a somewhat shorter working stroke. In FIG. 8, finally, the positioning of members 22 and 25 causes the shortest stroke of ram 18. The length of adjusted stroke may be read on indicator means 52 shown in FIG. 2. The indicator means comprises one or more scorings on the exposed end face of shaft portion 3-. and a second set of scorings on the exposed end face of handgrip member 32. The second set of scorings surrounds the scoring or scorings on the exposed end face of shaft portion 34 and enables the operator to immediately determine the angular position of eccentric 25 with respect to eccentric portion 22.

Cylindrical periphery of inner bushing 25 is rotatably received in an outer eccentric bushing 39', the latter being formed with a radial recess or groove 40 extending inwardly from its right-hand end face, as is shown in FIG. 4. Groove 4 receives the non-circular projection or head (see FIGS. 6 to 8) of a coupling bolt 41, the latter being preferably non-removably received in a bore provided in an outer cylindrical member or sleeve 42 which is retatably received in a cylindrical bore 13a" of wall 13".

Outer sleeve 42 is coaxial with portions 17, 17" of driving shaft 17 and coaxially receives the anti-friction hearing 24. Thus, shaft portion 17", inner sleeve 28, bearing 24 and the outer sleeve 42 are concentric and require very little space in head 13. Cylindrical member or sleeve 42 is held against axial displacements to the right of FIG. 4 by a retaining ring 43 which is fixed to wall 13 by means of bolts 44. An annular collar 42' on member 42 is received in a complementary annular recess in ring 43 and abuts against the outer face of wall 13" to prevent movements of sleeve 42 in a direction toward eccentric shaft portion 22. The right-hand central portion 42" of cylindrical member or adjusting sleeve 42 extends through the bore in annular retaining ring 43 and is formed with a peripheral zone of partly spherical contour. Portion 42" is received in the bore provided in an annular hub 46' forming part of an actuating and adjusting lever 46, the hub 46 being pivotable about a pair of coaxial and diametrically opposed pivot pins 45 shown in FIG. 5. It will be noted that, in FIG. 5, hub 46' and outer sleeve 42 are turned through about 90 degrees from their position of FIG. 4. Due to the partly spherical configuration of extension 42", hub 46 may be pivoted or tilted about members 45 when the lever 46 is swung in the direction of arrow A (PEG. 4) in a plane passing through the axis of shaft portions 17, 17''. At the same time, pins 45 connect lever 46 with the outer sleeve 42 so that they may rotate in unison when a locking member or bolt 47 is removed from one of a series of bores or recesses 43 provided in the retaining ring 43, as is shown in FIG. 2. It will be noted that the bolt 47 is disposed in a plane intersecting at right angles the plane of pins 45' and that the recesses or bores 43 are disposed on the periphery of a circle concentric with shaft portion 17 and cylindrical member 42. A tilting member in the form of a pin 49 is received in a bore 50 provided in the sleeve 42 and is constantly urged in the direction toward hub 46' by a coil spring 51 operating between the end wall in bore 5: and the adjacent end of tilting pin 49. The latters purpose is to constantly urge hub 46' and hence lever 46 into the position in which the end of locking bolt 4'7 extends into one of recesses 48. It will be observed that the length of bolt 47, and more particularly of its portion extending from the hub 46', is selected with a view to fully remove the bolt from a recess 48 when the springbiased lever 46 is tilted about coaxial pins 45 in the direction of arrow A, i.e. in the direction to compress the resilient member 51 The purpose of members 42 and 46 is to control the position of movable die member 14 with respect to stationary die member 15, and hence with respect to the work piece or blank (not shown), regardless of the length of stroke of ram 18. The adjustment is made by first tilting lever 46 in the direction of arrow A sufficiently to remove bolt 47 from one of bores or recesses 48, and by thereupon rotating the lever in clockwise or anticlockwise direction, as is indicated by the double arrow B in FIG. 2. The direction of levers rotation depends on whether the operator desires to move the die member 14 toward or away from the work piece. As before stated, sleeve 42, being connected with hub 46 of lever 46 by means of pins 45, also rotates and, over coupling member 41, causes rotation of eccentric bushing 3% about the inner ececntric bushing 25.

In the position of FIG. 6, eccentric member 39 is so adjusted that the movable die member 14 assumes its lowermost position. FIG. 7 shows the eccentric 39 in the same position and FIG. 8 in its uppermost position, i.e. in which the movable die member 14 is removed from contact with the work piece regardless of whether or not the ram 18 performs its working strokes. As soon as the desired adjustment in the position of movable die member 14 is made, the operator releases lever 46 whereby the spring 51 and pin 49 cause bolt 47 to enter a selected recess 48. In this manner, lever 46, outer sleeve 42 and eccentric 39 are prevented from unintentional rotation, for example, due to friction between eccentrics 25 and 39, as the spring 51 constantly urges lever 46 to pivot about pins 45 and thereby retains the bolt 47 in a selected recess 48.

As is best shown in FIG. 4, a particular feature of the novel stroke adjusting means and of the novel means for adjusting the position of movable die member is in that the entire system occupies very little space. This is accomplished by arranging eccentric members 25, 39 in surrounding relationship and by mounting said members substantially in the plane of connecting member 21 and ram 18. Moreover, the length of eccentric bushings 25, 39 does not exceed the length of eccentric shaft portion 22 which also contributes to savings in space and material. Still further, the actuating means for adjusting the positions of eccentrics 25, 39 also occupy very little space as they extend little beyond the outer face of supporting Wall 13", this being due to concentric disposition of sleeves 28 and 42.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characterisics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be Letters Patent is:

1. In a stamping machine, in combination: a ram having an upper end; means slidably guiding said ram for reciprocating movements in one direction; a driving shaft having an eccentric portion; an inner eccentric mounted in surrounding relationship about said eccentric portion; means for connecting said eccentric to said shaft in dilferent turned positions; an outer eccentric rotatably receiving said inner eccentric; means'for holding said outer eccentric against rotation With said inner eccentric, said means being turnable about the axis of said driving shaft for adjustment of the angular position of said outer eccentric, and being arrestable with respect to said ram guiding means for holding said outer eccentrio in adjusted angular positions; and connecting means receiving said outer eccentric and rotatable thereabout, said connecting means being swingably fixed to the upper end of said ram.

2. A stamping machine comprising, in combination: a driving shaft having an axis, a pair of coaxial portions and an eccentric portion; an inner eccentric mounted in surrounding relationship about said eccentric portion, having an end face and a recess in said end face; an inner sleeve including a projection extending into said recess for coupling same with said eccentric, said sleeve. surrounding one coaxial portion of said shaft; means for adjustably connecting said sleeve with said shaft; an outer eccentric rotatably receiving said inner eccentric, said outer eccentric having an end face and a recess in said end face; an outer sleeve including a projection extending into said last mentioned recess for coupling same with said outer eccentric, said outer sleeve surrounding said inner sleeve and being rotatably mounted; means for turning said outer sleeve and for arresting said outer sleeve in turned positions; connecting means receiving said outer eccentric and rotatable thereabout; a ram having one end swingably connected with said last mentioned means; the machine operating in such manner that, when said shaft rotates with the inner eccentric and with the inner sleeve in said outer eccentric and said outer sleeve, respectively, the connecting means reciprocates said ram :whereby the ram performs a stroke of a length determined by the angular position of said inner eccentric with respect to said eccentric portion, the position of said secured by 7 working stroke depending upon the angular position of said outer eccentric and of said outer sleeve.

3. A stamping machine comprising, in combination: a driving shaft having an axis, a pair of coaxial portions and an eccentric portion; an inner eccentric mounted in surrounding relationship about said eccentric portion, having an end face and a recess in said end face; an inner sleeve including a projection extending into said recess for coupling same with said eccentric, said sleeve surrounding one coaxial portion of said shaft; means for adjustably connecting said sleeve with said shaft and cornprising a haudgrip member non-rotatably and axially slidably connected with said sleeve for movement between two positions, said handgrip member and said one coaxial portion defining a releasable clutch connecting same for rotation when the handgrip member is in one of said positions and permitting independent rotation of said handgrip member with said sleeve and said eccentric relative to said shaft when the handgrip member is in the other of said positions, and resilient means operating between said one coaxial portion and said handgrip member for constantly urging the latter into said one position; an outer eccentric rotatably receiving said inner eccentric, said outer eccentric having an end face, a recess in said end face; an outer sleeve including a turnable pin extending into said last mentioned recess and being slidable therein for coupling same with said outer eccentric, said outer sleeve surrounding said inner sleeve and being rotatably mounted; means for turning said outer sleeve and for arresting said outer sleeve in turned positions; connecting means receiving said outer eccentric and rotatable thereabout; a ram having one end swingably connected with said last mentioned means; the machine operating in such manner that, when said shaft rotates with the inner eccentric and with the inner sleeve in said outer eccentric and said outer sleeve, respectively, the connecting means reciprocates said ram whereby the ram performs a stroke of a length determined by the angular position of said inner eccentric with respect to said eccentric portion, position of said working stroke depending upon the angular position of said outer eccentric and of said outer sleeve.

4. A machine of the character described which comprises, in combination: a driving shaft having an axis, a pair of coaxial portions, and an eccentric portion between said coaxial portions, one coaxial portion comprising external teeth parallel with the axis of said shaft; an inner eccentric mounted in surrounding relationship about said eccentric portion; an inner sleeve coupled with said eccentric and surrounding said coaxial portion; a handgrip member non-rotatably and axially slidably coupled with said sleeve for movements between two positions, said handgrip member having a bore and internal teeth in said bore meshing with the teeth of said coaxial portion when the handgrip member is in one of said positions and spaced from said last mentioned teeth when the handgrip member is in the other position; resilient means operating between said coaxial portion and said handgrip member for constantly urging the latter into said one position; an outer eccentric rotatably receiving said inner eccentric; an outer sleeve coupled with said outer eccentric, surrounding said inner sleeve, and rotatably mounted; means for turning said outer sleeve and for arresting said outer sleeve in turned positions; connecting means receiving said outer eccentric and rotatable thereabout; a ram having one end swingably connected with said last mentioned means and another end; the machine operating in such manner that, when the shaft rotates with the inner eccentric, with the inner sleeve and with the handgrip member, the connecting means reciprocates said ram whereby the ram performs a stroke of a length determined by the angular position of said inner eccentric with respect to said eccentric portion, said angular position being adjustable by moving said handgrip member into said other position and rotating same together with said inner sleeve Q and said inner eccentric with respect to said shaft, and the position of said working stroke depending upon the angular position of saidouter eccentric and said outer sleeve.

5. A stamping machine comprising, in combination: a driving shaft having a pair of coaxial portions and an eccentric portion therebetween; an inner eccentric mounted in surrounding relationship about said eccentric portion; an inner sleeve coupled with said inner eccentric and surrounding one coaxial portion of said shaft; means for adiustably connecting said sleeve with said shaft; an outer eccentric rotatably receiving said inner eccentric; an outer sleeve having a turnable pin coupled with said outer eccentric and surrounding said inner sleeve, said outer sleeve being rotatably mounted; a retaining member for rotatably holding the outer sleeve against axial movements; an actuating lever member for said outer sleeve; means for so connecting the lever member with said outer sleeve that the lever member is tiltable in a plane passing through the axis of said shaft between two positions; clutch means disposed between said lever member and said retaining member comprising a bolt connectedto one of said members at its side facing the other member, the other member having a plurality of recesses disposed on the periphery of a circle concentric with said outer sleeve and one of said recesses receiving said bolt when the lever member is in one of said positions, said bolt being moved away from said recesses when the lever member is in the other position; resilient means for constantly urging the lever member into said one position; connecting means receiving said outer eccentric and rotatable thereabout; a ram having one end swingably connected with said last mentioned means; the machine operating in such manner that, when said shaft rotates with the inner eccentric and with the inner sleeve in said outer eccentric and said outer sleeve, respectively, the connecting means reciprocates the ram whereby the ram performs a stroke of a length determined by the angular position of said inner eccentric and said inner sleeve with respect to the eccentric portion of said shaft, the position of said working stroke depending on the angular position of said outer eccentric and of said outer sleeve, said last mentioned angular position being adjustable by moving the lever member into said other position and rotating same together with said outer sleeve and with said outer eccentric relative to said retaining member.

6. A stamping machine comprising, in combination: a driving shaft having an axis, a pair of coaxial portions and an eccentric portion therebetween an inner eccentric mount d in surrounding relationship about said eccentric portion; an inner sleeve coupled with said inner eccentric and surrounding one coaxial portion of said shaft; means for adjustably connecting said sleeve with said shaft; an outer eccentric rotatably receiving said inner eccentric; an outer sle ve having a turntable pin coupled with said outer eccentric and surrounding said inner sleeve, said outer sleeve being rotatably mounted, said outer slee e further comprising an end face turned away from said outer eccentric and having a bore in said end face paraliel with the axis of said shaft; a retaining member for rotatably holding the outer slecve against axial movements; an actuating lever member for said outer sleeve; means for so connecting the lever member with said outer sleeve that the lever member is tiltablc in a plane passing through the axis of said shaft between two positions; clutch means disposed between said lever member and said retaining member comprising a bolt connected to one of said members at its side facing the other member, the other member having a plurality of recesses disposed on the periphery of a circle concentric with said outer sleeve and one of said recesses receiving said bolt when the lever member is in one of said positions, said bolt being moved away from said recesses when the lever member is in the other position; resilient means in the bore of said outer sleeve; a tilting member in said bore having an end in contact with said lever member for 9 10 constantly urging the lever member into said one posi- References Cited in the file of this patent tron under the action of said resilient means; connecting UNITED STATES PATENTS means receiving said outer eccentric and rotatable thereabout; a ram having one end swingably connected with 459,597 Stiles Sept. 15, 1891 said last mentioned means; the machine operating in such 5 1,565,264 Dubi Dec. 15, 1925 manner that, when said shaft rotates with the inner ec- 2,006,779 Terrell July 2, 1935 centric and with the inner sleeve in said outer eccentric 2, 65,222 Benes Dec. 9, 1941 and said outer sleeve, respectively, the connecting means 2,477,537 Doutt Aug. 2, 1949 reciprocates the ram whereby the ram performs a stroke 2,561,344 Cutler et a1. July 24, 1951 of a length determined by the angular position of said 10 2,592,237 Bradley Apr. 8, 1952 inner eccentric and said inner leeve with respect to the 2,703,032 Grove Mar. 1, 1955 eccentric portion of said shaft, the position of said work- 2,834,223 Sternad May 13, 1958 ing stroke depending on the angular position of said outer eccentric and of said outer sleeve, said last men- FOREIGN PATENTS tioned angular position being adjustable by moving the 15 470,773 France Sept, 29, 19 4 lever member into said other position and rotating same 530,452 France Om 3 1921 together with said outer sleeve and with said outer eccen- 317,6 5 Germany Oct 13 1951 tric relative to said retaining member. 

